Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 71. (Budapest 1979)

Hably, L.: Some data to the Oligocene flora of the Kiscellian Tard Clay, Hungary

ANNALES HISTORICO-NATURALES MUSEI NATIONALIS HUNGARICI Tomus71. Budapest 1979. Some Data to the Oligocène Flora of the Kiscellian Tard Clay, Hungary by L. HABLY, Budapest Abstract — Deep sunk H drillings included a rich macroflora in Budapest: H-ll, H-14, H-15, H-16, H-17, H-18 have been tested. The flora was recovered from the Tard Clay formation dating from Kiscellian stage, i.e. Lower and Middle Oligocène. Two levelmarking species were detected: Libocedrites salicornioides (UNG.) ENDL. and Doliostrobus hungaricus (RÁSKY) BÛZEK, HOLY & KVACEK. On floral basis two plant communities can be distinguished here: lakeshores and moorlands, and hilly region. With 12 plates and 1 Table. The age of the flora The full geological-paleontological testing of the drill samples indicates that over 90 percent of the layers contains plantfloral fossils of Tard Clay. The drillings are of Kiscell Clay and Buda Marl which do not contain leaf remains in any considerable quantity. The Tard Clay dates from the LowerMiddle Oligocène. It belongs to the Kiscellian stage dateble also floristically as to belong to the Lower-Middle Oligocène. It greatly resembles the flora of Kiseged, the Lower-Middle Oligocène of Bohemia, and the Lower Oligocène flora of Mera (Roumania). Several test samples originating from within a restricted area made it possible to define local zones on the basis of the flora. These seem to be useful also in later researches. Zizyphus zizyphoides which is generally characteristic of the Lower Oligocène, as well as Rhodomyrtophyllum rossmässleri a characteristically paleogene element cannot be used for closer levelling, since the latter occurred only in two drillings. But the presence of Doliostrobus hungaricus deserves attention; this is characteristic of the Lower-Middle Oligocène of the Czech Central Mountains. It was first discovered at 53 m. in the H-16 Vörösvári road bore-hole, and it is found even at 57 meters. It is present already at 44 m. and in great quantities in the sediment below. In H-18 it is at 40.5 m. and also at 55.5 m. The level of Doliostrobus is well definable, its highest position is at 40.5 m. in H-18. (Note : the order of the bore-holes is not identical with their serial numbers; the actual order is: 11, 14, 17, 16, 15, 18.) It is to be seen that the Doliostrobus level shows a regular rise in the direction of H-18. This tendency is shown even more markedly by the Libocedrites salicornioides level. This species was found also in H-17 bore-hole, where it occurs between 53.1 m.-60.5 m. The drilling was completed at this depth. In H-16 it occurs at 43.8 m. It is missing from H-15, probably on account of sampling conditions; it is to be found in the adjacent H-18 already at 24.4 m. In Hungary it has been found in the Tard Clay formation, at Budaújlak (VARGA 1956) and Kiseged (NOVAK 1950). Of the two Doliostrobus is level-marking species over a large area of the Central Paratethys, partly on account of its above-mentioned occurrence in the Czech Central Mountains and partly owing to its presence in Hungary. Araucaria hungarica and Sequoia sternbergii described by RÁSKY (1943) have also proved to be Doliostrobus as shown by BÛZEK, HOLY & KVAÍEK (1968). This is testified also by the fossils recovered from the drillings marked H. The fossils from the Kiseged flora classified as Sequoia sternbergii (NOVAK 1950) is probably also Doliostrobus. In Hungary Libocedrites salicornioides is also a levelmarking species. In addition to the latest drillings, it was also found in the Tard Clay at Óbuda (VARGA 1956) and at Kiseged (NOVAK 1950). In the area of the Czech Central Mountains it dates from Egerian whereas in Hungary it has not yet been found in this stage. From the point of view of dating Platanus neptuni should also be mentioned. The species was identified and described in 1967 (BÛZEK, HOLY & KVACEK 1967) according to earlier works the fossils of this species are mentioned under several names which were revised by the above authors. It was recorded under Ceratopetalum auriculatum (ANDREÁNSZKY & NOVAK 1957), Callicoma egedensis (ANDREÁNSZKY & NOVAK 1957), Callicoma microphylla (ANDREÁNSZKY 1959), Cunonia oligocenica (ANDREÁNSZKY & NOVAK 1957) from the Middle Oligocène Vécsey valley Ann. Hist.-nat. Mus. Nat. Hung., 71, 1979 3 Természettudományi Múzeum Évkönyve 1979